1. Field of the Invention
The present invention relates to a method for forming an oxide semiconductor film or an insulating film, and to a method for manufacturing a semiconductor device with the use of the oxide semiconductor film or the insulating film.
Note that a semiconductor device in this specification refers to general devices which can function by utilizing semiconductor characteristics; for example, a semiconductor element such as a transistor, a semiconductor circuit including a semiconductor element, an electro-optical device such as a display device, and an electronic device are all semiconductor devices.
2. Description of the Related Art
Transistors used for most flat panel displays typified by a liquid crystal display device and a light-emitting display device are formed using silicon semiconductors such as amorphous silicon, single crystal silicon, and polycrystalline silicon provided over glass substrates. Further, transistors formed using such silicon semiconductors are used in integrated circuits (ICs) and the like.
In recent years, attention has been drawn to a technique in which, instead of a silicon semiconductor, a metal oxide exhibiting semiconductor characteristics is used for transistors. Note that, in this specification, a metal oxide exhibiting semiconductor characteristics is referred to as an oxide semiconductor.
For example, a technique is disclosed in which a transistor is manufactured using zinc oxide or an In—Ga—Zn—O-based oxide as an oxide semiconductor and the transistor is used as a switching element or the like of a pixel of a display device (see Patent Documents 1 and 2). Further, concerning a transistor using an oxide semiconductor, a technique in which oxygen is introduced into an oxide semiconductor by an ion implantation method or an ion doping method is disclosed (see Patent Document 3).